Position location systems are used to locate, and track the movement of, persons or objects within a building or similar enclosed facility. For example, in a large medical facility such as a hospital, a position location system may be used to determine the exact location of a critical care physician or nurse, or certain emergency equipment such as a "code blue" cart. Also, such a system may be used to track the movement of employees and inventory in a manufacturing facility, such as an automobile manufacturing plant or semiconductor integrated circuit fabrication plant. Typically, a small transmitter is attached to each object to be tracked. The transmitter radiates a unique, identification signal. A number of receivers are strategically positioned to detect the radiated signals in different areas throughout the facility. Consequently, the object of interest may be tracked throughout the facility by following the movement of the detected signals.
For example, U.S. Pat. No. 5,062,151 discloses a system for locating personnel at a large facility. A portable, infrared transmitter is attached to each person to be located. Each transmitter radiates a unique, coded signal. A plurality of fixed, infrared receivers are positioned to cover different areas of the facility. Each receiver is capable of sensing and storing any of the unique signals radiated by the transmitters. A microcomputer polls each fixed receiver and, in response to a request to locate a certain individual, visually displays the location of the receiver at which the individual was most recently seen. Each room in the facility has a telephone. Upon receiving a call for an individual, an operator enters the individual's name into the computer, which directs the call to the telephone nearest the individual. However, the use of an operator to receive and enter the incoming calls increases both the time needed to connect the calls and hence the overall expense of the locating system. Furthermore, this patent discloses no specific system or method for directing an incoming call to the individual of interest.
U.S. Pat. No. 5,155,761 discloses a system and method for answering incoming telephone calls. Outside telephone calls are coupled through a telephone control switch to a "robot" controller, which is in turn controlled by a central processing unit. The control switch includes an ACD/PBX switchboard with attendants or operators. The robot controller is connected to a host computer and other "resources" such as facsimile machines or communications modems. Incoming calls are allocated by the ACD/PBX system to available resources or attendants. In the event that the resources or attendants are unavailable, the robot controller advises the caller with a recorded message that the resources are busy, and provides a time when the call is expected to be returned. However, the use of attendants to place incoming calls directly to individuals increases the connect time and overall expense of the system.
Accordingly, a need exists for a position location system that automatically locates an individual or object in response to a telephone caller's inquiry, and also directs the call to the telephone nearest that individual or object.